» Tue May 08, 2012 5:53 am
http://imperial-library.info/content/sithis should clear some things up (also increases your Alteration skill!)
A "void" is a simple way of describing him. There is also a description that he is everything that is evil and sinister.
In my understanding, Sithis is not a "physical" being. He is a perspective on life. He is metaphysical. When a DB Assassin carries out a Contract, it may be considered brutal murder, but to the Black Hand, it is "the work of Sithis."
When one sees darkness in the light, one finds Sithis. Shadowmere can be considered a physical manifestation of Sithis' power, but this is drawing a longbow.
In fact, the evil inside good ol' Akatosh, Sithis' influence, caused him "to split in half" and release Lorkhan. The Night Mother is a spirit inside a corpse because she discovered the true darkness inside herself, Sithis. When Lorkhan disappeared, he left a "Sithis-shaped hole," because the darkness that was present in the Divines as Lorkhan had disappeared, and needed to be replaced...